The present invention relates to a rolling bearing apparatus for vehicles for rotatably supporting an axle of a vehicle such as an automobile or the like on a vehicle body. More specifically, the present invention relates to a sensor assembly and a seal apparatus incorporated into a rolling bearing apparatus for vehicles.
Conventionally, there is a bearing apparatus for rotatably supporting an axle of an automobile with respect to a vehicle body, comprising a rotation detector used for ABS (anti-lock brake system) or the like (for example, refer to Japanese Laid-Open Patent Application Publication No. 8-43411). With such a bearing apparatus, a rolling member is interposed between the respective raceway surfaces of an inner ring outwardly fitted to the axle and serving as a rotating ring and an outer ring fixed to the vehicle body and serving as a fixed ring, and a clearance between the inner and the outer rings is sealed by a seal apparatus. A rotation detector is constituted so that a change in a magnetic field of a pulser ring fixed to the inner ring constituting the rotating ring is detected by a sensor and the detection signal is transmitted to an electronic circuit of the vehicle body via a wire harness.
Generally, the sensor is fixed to a knuckle and the electronic circuit is provided on the vehicle body. Therefore, since the knuckle is connected to a damper against swinging of the vehicle body during traveling, vibration of the vehicle body is not transmitted to the knuckle. Therefore, while the electronic circuit provided on the vehicle body vibrates with the swinging of the vehicle body, the sensor fixed to the knuckle is not affected by vibration of the vehicle body. Thus, there is the concern that the wire harness for connecting the sensor and the electronic circuit may be broken by vibration of the vehicle body.
In addition, in order to save space, a sensor for the latest ABS is contained in the seal apparatus, which is a seal pack and which is fitted on a bearing apparatus. Therefore, there is the problem that if the wire harness breaks and the ABS sensor is in an abnormal state, the entire hub unit, which contains the bearing apparatus, has to be replaced, making maintenance laborious and leading to expensive costs.